Child resistant safety closures comprising two nested closure members are well known. Typically, outer and inner cap members are provided with cooperating sets of lugs which engage each other when the outer closure is rotated in the direction to remove the closure from a container. A plurality of spring fingers on the inner surface of a top panel of the outer closure member urge the outer closure member away from the inner closure member and prevent engagement of the lugs. The outer surface of the top panel of the inner closure member is formed with ramps which are associated with the outer cap member spring fingers so that when the outer cap member is rotated relative to the inner cap member in a direction to apply the closure to a container the spring fingers engage the ramps to cause the cap members to rotate together. When the outer cap member is rotated in the opposite, or unscrewing, direction the spring fingers ride over the ramps to prevent accidental or unwanted removal of the closure. Only when the closure is rotated in the unscrewing direction and an axial force is simultaneously applied to the outer closure member the cooperating lugs are interengaged to unthread the inner closure member from the container.
The present invention seeks to provide improvements in or relating to such closures.
According to a first aspect of the present invention there is provided a child-resistant closure for a container, the closure comprising outer and inner nested caps each having a top panel and a side skirt depending generally peripherally therefrom, said outer cap loosely generally encompassing said inner cap to allow relative rotary and axial movement there between, the outer and inner caps having corresponding drive formations which can be brought into driving engagement when the caps are moved axially towards one another to a first axial position, one of the inner and outer caps comprising one or more spring members for urging the inner and outer caps axially away from each other to a second axial position, the other of the inner and outer caps comprising one or more ramps, the spring member(s) providing a biasing force to maintain said outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position so as to drive the outer and inner caps together in a screwing direction, but slipping over the ramp(s) freely in an unscrewing direction, downward pressure on the outer cap overcoming the spring finger bias to move the caps to the first axial position to allow unscrewing of the closure using the inner and outer cap drive formations, in which the external surface of the inner cap side skirt includes one or more axial ribs for allowing venting when the outer and inner caps are initially assembled together.
In some embodiments the assembly rib is formed integrally with an inner cap drive formation. This can be used, for example, to strengthen the formation and may allow for light-weighting of the member by removing material.
The rib may connect to an edge of the drive formation which, in use, engages drivingly with a drive formation on the outer cap.
The rib may extend along substantially the entire length of the skirt.
Each drive formation on the inner cap may have a respective rib.
In some embodiments the periphery of the inner cap top panel is provided with a plurality of castellations.
The or each rib may connect to an edge of a respective castellation.
The castellations may be generally U-shape in plan.
The castellations may each comprise a first radially extending side wall upstanding from the top panel and a second radially extending sidewall upstanding from the top panel, said first and second side walls being located at or towards the periphery of the top panel and being mutually spaced, the first and second side walls joined at one end by an arcuate cross wall.
In some embodiments the assembly rib extends from the first side wall of each castellation.
The first side wall may be joined to the assembly rib by an inclined wall section.
The castellations may be thinned in non-functioning areas.
The ribs may be mutually spaced around the external surface of the inner cap side skirt, and the circumferential extent of the ribs may be less than the circumferential extent of the spacing therebetween.
According to a further aspect there is provided a child-resistant closure for a container, the closure comprising outer and inner nested caps each having a top panel and a side skirt depending generally peripherally therefrom, said outer cap loosely generally encompassing said inner cap to allow relative rotary and axial movement there between, the outer and inner caps having corresponding drive formations which can be brought into driving engagement when the caps are moved axially towards one another to a first axial position, one of the inner and outer caps comprising one or more spring members for urging the inner and outer caps axially away from each other to a second axial position, the other of the inner and outer caps comprising one or more ramps, the spring member(s) providing a biasing force to maintain said outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position so as to drive the outer and inner caps together in a screwing direction, but slipping over the ramp(s) freely in an unscrewing direction, downward pressure on the outer cap overcoming the spring finger bias to move the caps to the first axial position to allow unscrewing of the closure using the inner and outer cap drive formations, in which for the or each ramp a respective detent projection is provided which projects above the plane of the top panel and lies in the path of travel of the spring member, the projection supports the spring member when in driving engagement with the ramp to resist deformation of the spring member as it transmits force to the ramp face, the profile of the projection matches the profile of the region of the spring member in contact therewith.
According to a further aspect there is provided a child-resistant closure for a container, the closure comprising outer and inner nested caps each having a top panel and a side skirt depending generally peripherally therefrom, said outer cap loosely generally encompassing said inner cap to allow relative rotary and axial movement there between, the outer and inner caps having corresponding drive formations which can be brought into driving engagement when the caps are moved axially towards one another to a first axial position, one of the inner and outer caps comprising one or more spring members for urging the inner and outer caps axially away from each other to a second axial position, the other of the inner and outer caps comprising one or more ramps, the spring member(s) providing a biasing force to maintain said outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position so as to drive the outer and inner caps together in a screwing direction, but slipping over the ramp(s) freely in an unscrewing direction, downward pressure on the outer cap overcoming the spring finger bias to move the caps to the first axial position to allow unscrewing of the closure using the inner and outer cap drive formations, in which the ramp is profiled to support the spring member substantially continuously as the member passes over it in the unscrewing direction.
The profile of the ramp may change constantly as the ramp height increases.
The present invention also provides an inner cap for a child-resistant container closure of the type comprising outer and inner nested caps each having a top panel and a side skirt depending generally peripherally therefrom, said outer cap loosely generally encompassing said inner cap to allow relative rotary and axial movement there between, the outer and inner caps having corresponding drive formations which can be brought into driving engagement when the caps are moved axially towards one another to a first axial position, one of the inner and outer caps comprising one or more spring members for urging the inner and outer caps axially away from each other to a second axial position, the other of the inner and outer caps comprising one or more ramps, the spring member(s) providing a biasing force to maintain said outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position so as to drive the outer and inner caps together in a screwing direction, but slipping over the ramp(s) freely in an unscrewing direction, downward pressure on the outer cap overcoming the spring finger bias to move the caps to the first axial position to allow unscrewing of the closure using the inner and outer cap drive formations, in which the external surface of the inner cap side skirt includes one or more axial ribs for allowing venting when the outer and inner caps are initially assembled together.
The present invention also provides an inner cap as described herein.
The present invention also provides an outer cap as described herein.
The present invention also provides a closure as described herein in combination with a container.
Different aspects and/or embodiments of the invention may be used separately or together.
Further particular and preferred aspects of the present invention are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with the features of the independent claims as appropriate, and in combination other than those explicitly set out in the claims.
The present invention will now be more particularly described with reference to, and as shown in, the accompanying drawings.